/*
 * Copyright (C) 2009 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.util.Comparator;
import java.util.Spliterator;
import javax.annotation.Nullable;

/**
 * List returned by {@code ImmutableSortedSet.asList()} when the set isn't empty.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible(emulated = true)
@SuppressWarnings("serial")
final class ImmutableSortedAsList<E> extends RegularImmutableAsList<E> implements SortedIterable<E> {
    ImmutableSortedAsList(ImmutableSortedSet<E> backingSet, ImmutableList<E> backingList) {
        super(backingSet, backingList);
    }

    @Override
    ImmutableSortedSet<E> delegateCollection() {
        return (ImmutableSortedSet<E>) super.delegateCollection();
    }

    @Override
    public Comparator<? super E> comparator() {
        return delegateCollection().comparator();
    }

    // Override indexOf() and lastIndexOf() to be O(log N) instead of O(N).

    @GwtIncompatible // ImmutableSortedSet.indexOf
    // TODO(cpovirk): consider manual binary search under GWT to preserve O(log N) lookup
    @Override
    public int indexOf(@Nullable Object target) {
        int index = delegateCollection().indexOf(target);

        // TODO(kevinb): reconsider if it's really worth making feeble attempts at
        // sanity for inconsistent comparators.

        // The equals() check is needed when the comparator isn't compatible with
        // equals().
        return (index >= 0 && get(index).equals(target)) ? index : -1;
    }

    @GwtIncompatible // ImmutableSortedSet.indexOf
    @Override
    public int lastIndexOf(@Nullable Object target) {
        return indexOf(target);
    }

    @Override
    public boolean contains(Object target) {
        // Necessary for ISS's with comparators inconsistent with equals.
        return indexOf(target) >= 0;
    }

    @GwtIncompatible // super.subListUnchecked does not exist; inherited subList is valid if slow
    /*
     * TODO(cpovirk): if we start to override indexOf/lastIndexOf under GWT, we'll want some way to
     * override subList to return an ImmutableSortedAsList for better performance. Right now, I'm
     * not sure there's any performance hit from our failure to override subListUnchecked under GWT
     */
    @Override
    ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) {
        ImmutableList<E> parentSubList = super.subListUnchecked(fromIndex, toIndex);
        return new RegularImmutableSortedSet<E>(parentSubList, comparator()).asList();
    }

    @Override
    public Spliterator<E> spliterator() {
        return CollectSpliterators.indexed(size(),
                ImmutableList.SPLITERATOR_CHARACTERISTICS | Spliterator.SORTED | Spliterator.DISTINCT,
                delegateList()::get, comparator());
    }
}
